1. Field of the Invention
The present invention relates to a cube and method of making same.
2. Background Art
Generally, to make a polarizing cube or a beam splitting cube a prism with a coating (e.g., a dielectric stack) is optically contacted (e.g., bonded) to an uncoated prism. Many parameters must be taken into consideration when optically contacting the prisms to ensure they remain bonded and that they have a certain amount of optical compatibility. Being compatible ensures the lowest amount of reflection occurs when light travels between the bonded surfaces. Problems with adherence and reflection are more common with cubes manufactured for systems using shorter wavelengths of light (e.g., vacuum ultra violet (VUV) and deep ultra violet (DUV) light). In the case of cubes used in VUV and DUV systems, the materials available to manufacture the cubes are very limited for performance reasons, and are typically not conductive to optical contacting. To compound the problem, there are strict environmental parameters that must be maintained for DUV applications that are contrary to current contacting techniques. To overcome these problems, different types of contacting processes have been developed. However, these processes have produced other problems, such as low throughput that can dramatically reduce the effectiveness of the system. For example, in a lithography system the output light is too weak to write patterns on a substrate.
Therefore, what is needed is a process of making a cube that can be used with any wavelength of light in which the bonded prisms are securely optically contacted and optically compatible, which substantially eliminates any reflectivity between bonded surfaces and increases throughput of light in a system using the cube.
An embodiment of the present invention provides a method of making a cube. The method includes the steps of performing a multi-layer coating process to form a multi-layer coating on a prism, performing a contact layer coating process to form a contact layer coating on top of the multi-layer coating, and coupling the prism to an uncoated prism. The contacting layer coating process includes the step of forming a silicon dioxide (SiO2) or fused silica layer as the contact layer.
Another embodiment of the present invention provides a cube including an uncoated prism and a coated prism coupled to the uncoated prism. The coated prism includes a first coating section having a multi-layered coating and a second coating section formed on top of the first coating section. The second coating section has a contact layer coating, which can be a SiO2 or fused silica coating.
advantage of the cube made by the process according to embodiments of the present invention is that it allows for secure bonding between an uncoated and coated prism though use of the contact layer, while still providing high throughput and low reflection between bonded surfaces.
Further embodiments, features, and advantages of the present inventions, as well as the structure and operation of the various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.